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Shenggen Huang, Jian Sun, Jian Yan, Jia-Qin Liu, Weijie Wang, Qingqing Qin, Wenping Mao, Wei Xu, Yu Cheng Wu, Junfeng Wang
In this work, Al-doped MnO2 (Al-MO) nanoparticles have been synthesized by a simple chemical method with the aim to enhance cycling stability. At room temperature and 50 °C, the specific capacitances of Al-MO are well maintained after 10000 cycles. Compared with pure MnO2 nanospheres (180.6 F g-1 at 1 A g-1), Al-MO also delivers an enhanced specific capacitance of 264.6 F g-1 at 1 A g-1. During cycling test, Al-MO exhibited relatively stable structure initially and transformed to needle-like structures finally both at room temperature and high temperature...
February 28, 2018: ACS Applied Materials & Interfaces
Timur M Rvachov, Hyungmok Son, Juliana J Park, Pascal M Notz, Tout T Wang, Martin W Zwierlein, Wolfgang Ketterle, Alan O Jamison
We perform photoassociation spectroscopy in an ultracold 23Na-6Li mixture to study the c3Σ+ excited triplet molecular potential. We observe 50 vibrational states and their substructure to an accuracy of 20 MHz, and provide line strength data from photoassociation loss measurements. An analysis of the vibrational line positions using near-dissociation expansions and a full potential fit is presented. This is the first observation of the c3Σ+ potential, as well as photoassociation in the NaLi system.
January 30, 2018: Physical Chemistry Chemical Physics: PCCP
M V Karg, A Bosch, D Kannenkeril, K Striepe, C Ott, M P Schneider, F Boemke-Zelch, P Linz, A M Nagel, J Titze, M Uder, R E Schmieder
BACKGROUND AND AIMS: Sodium tissue content by 23Na magnetic resonance imaging (Na-MRI) has been validated in experimental and human studies. SGLT-2 inhibition blocks the reabsorption of glucose and of sodium in the proximal tubular cells in a 1:1 fashion. We hypothesized that SGLT-2 inhibition in patients with type 2 diabetes characterized by sodium retention leads to decreased tissue sodium content due to its pharmacological action. MATERIALS AND METHODS: In a prospective double blind, placebo controlled, cross-over trial 59 patients (61 ± 7...
January 4, 2018: Cardiovascular Diabetology
Alina Gilles, Armin M Nagel, Guillaume Madelin
We present a feasibility study of sodium quantification in a multicompartment model of the brain using sodium (23Na) magnetic resonance imaging. The proposed method is based on a multipulse sequence acquisition and simulation at 7 T, which allows to differentiate the 23Na signals emanating from three compartments in human brain in vivo: intracellular (compartment 1), extracellular (compartment 2), and cerebrospinal fluid (compartment 3). The intracellular sodium concentration C 1 and the volume fractions α 1, α 2, and α 3 of all respective three brain compartments can be estimated...
December 12, 2017: Scientific Reports
YongHyun Ha, Chang-Hoon Choi, Wieland A Worthoff, Aliaksandra Shymanskaya, Michael Schöneck, Antje Willuweit, Jörg Felder, N Jon Shah
A folded four-ring quadrature birdcage coil was designed and constructed with a double-tune configuration of an outer high-pass coil for1 H (400 MHz) and inner low-pass coil for23 Na (105.72 MHz at 9.4 T). The coil was evaluated on the bench and in the scanner, comparing its performance with that of single-tuned coils and a large four-ring coil. All coils were tuned and matched and the isolation between two quadrature ports was found to be better than -13.7 dB for1 H and -27 dB for23 Na. Signal-to-noise ratios (SNRs) were calculated and23 Na flip angle maps were acquired...
January 2018: Journal of Magnetic Resonance
Yuyu Li, Zhi Deng, Jian Peng, Enyi Chen, Yao Yu, Xiang Li, Jiahuan Luo, Yangyang Huang, Jinlong Zhu, Chun Fang, Qing Li, Jiantao Han, Yunhui Huang
Here, a P2-type layered Na2 Zn2 TeO6 (NZTO) is reported with a high Na+ ion conductivity ≈0.6×10-3  S cm-1 at room temperature (RT), which is comparable to the currently best Na1+n Zr2 Sin P3-n O12 NASICON structure. As small amounts of Ga3+ substitutes for Zn2+ , more Na+ vacancies are introduced in the interlayer gaps, which greatly reduces strong Na+ -Na+ coulomb interactions. Ga-substituted NZTO exhibits a superionic conductivity of ≈1.1×10-3  S cm-1 at RT, and excellent phase and electrochemical stability...
January 24, 2018: Chemistry: a European Journal
Pieter Geysens, Vijay Shankar Rangasamy, Savitha Thayumanasundaram, Koen Robeyns, Luc Van Meervelt, Jean-Pierre Locquet, Jan Fransaer, Koen Binnemans
Electrolytes consisting of sodium bis(fluorosulfonyl)imide (NaFSI) dissolved in glymes (monoglyme, diglyme, and triglyme) were characterized by FT-Raman spectroscopy and13 C,17 O, and23 Na NMR spectroscopy. The glyme:NaFSI molar ratio was varied from 50:1 to 1:1, and it was observed that, in the dilute electrolytes, the sodium salt is completely dissociated into solvent separated ion pairs (SSIPs). However, contact ion pairs (CIPs) and aggregates (AGGs) become the predominant species in more concentrated solutions...
January 11, 2018: Journal of Physical Chemistry. B
Daniela Ekendahl, Peter Rubovic, Pavel Žlebcík, Ondrej Huml, Helena Malá
Salt (NaCl) represents a radiation sensitive material with a considerable potential for dosimetry in mixed radiation fields of photons and neutrons. In consequence of a gamma radiation exposure, it exhibits a strong luminescence signal following stimulation with blue light. Optically stimulated luminescence (OSL) technique can be used for measurement. Photon dose reconstruction can be done using so-called Single-Aliquot Regenerative-dose protocol. However, a part of OSL signal is caused by NaCl self-irradiation resulting from neutron reactions...
August 22, 2017: Radiation Protection Dosimetry
Irina I Ivanova, Yury G Kolyagin, Ivan A Kasyanov, Alexander V Yakimov, Tatiana O Bok, Dmitry N Zarubin
Time-resolved (13) C, (23) Na, (27) Al, and (29) Si MAS NMR has been applied in situ for monitoring the hydrothermal synthesis of zeolite BEA. Isotopic labelling with (29) Si and (13) C isotopes has been used to follow the fate of siliceous species and structure directing agent (((13) CH3 -CH2 )4 NOH). Two mechanistic pathways, namely solution-mediated and solid-solid hydrogel rearrangement have been distinguished for two synthesis procedures studied. The mechanisms of structure-directing behavior of TEA(+) cations in two reaction pathways have been elucidated...
September 20, 2017: Angewandte Chemie
Régis Guégan, Emmanuel Veron, Lydie Le Forestier, Makoto Ogawa, Sylvian Cadars
The aggregation of surfactants on solid surfaces as they are adsorbed from solution is the basis of numerous technological applications such as colloidal stabilization, ore flotation, and floor cleaning. The understanding of both the structure and the dynamics of surfactant aggregates applies to the development of alternative ways of preparing hybrid layered materials. For this purpose, we study the adsorption of the triethylene glycol mono n-decyl ether (C10E3) nonionic surfactant onto a synthetic montmorillonite (Mt), an aluminosilicate clay mineral for organoclay preparation with important applications in materials sciences, catalysis, wastewater treatment, or as drug delivery...
September 12, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
Krista A Shisler, Rachel U Hutcheson, Masaki Horitani, Kaitlin S Duschene, Adam V Crain, Amanda S Byer, Eric M Shepard, Ashley Rasmussen, Jian Yang, William E Broderick, Jessica L Vey, Catherine L Drennan, Brian M Hoffman, Joan B Broderick
Pyruvate formate-lyase activating enzyme (PFL-AE) is a radical S-adenosyl-l-methionine (SAM) enzyme that installs a catalytically essential glycyl radical on pyruvate formate-lyase. We show that PFL-AE binds a catalytically essential monovalent cation at its active site, yet another parallel with B12 enzymes, and we characterize this cation site by a combination of structural, biochemical, and spectroscopic approaches. Refinement of the PFL-AE crystal structure reveals Na(+) as the most likely ion present in the solved structures, and pulsed electron nuclear double resonance (ENDOR) demonstrates that the same cation site is occupied by (23)Na in the solution state of the as-isolated enzyme...
August 30, 2017: Journal of the American Chemical Society
Markus Krengel, Anna-Lena Hansen, Maximilian Kaus, Sylvio Indris, Niklas Wolff, Lorenz Kienle, David Westfal, Wolfgang Bensch
The ternary compound CuV2S4 exhibits an excellent performance as anode material for sodium ion batteries with a high reversible capacity of 580 mAh g(-1) at 0.7 A g(-1) after 300 cycles. A Coulombic efficiency of ≈99% is achieved after the third cycle. Increase of the C-rate leads to a drop of the capacity, but a full recovery is observed after switching back to the initial C-rate. In the early stages of Na uptake first Cu(+) is reduced and expelled from the electrode as nanocrystalline metallic Cu. An increase of the Na content leads to a full conversion of the material with nanocrystalline Cu particles and elemental V embedded in a Na2S matrix...
June 16, 2017: ACS Applied Materials & Interfaces
Sohei Sukenaga, Pierre Florian, Koji Kanehashi, Hiroyuki Shibata, Noritaka Saito, Kunihiko Nakashima, Dominique Massiot
The description of the structure of aluminosilicate glasses is more often centered on its cationic constituents, and oxygen ions determine their connectivity, directly impacting the physical properties of those disordered materials. A very powerful approach to ascertain this short- to medium-range order is to use (17)O NMR, but up to now the speciation of the chemical bonds was only ambiguously achieved for multicomponent glasses. Here, we propose to directly probe the very scarcely explored through-bond correlations using (17)O{(27)Al} and (17)O{(23)Na} solid-state nuclear magnetic resonance (NMR) double-resonance experiments...
May 8, 2017: Journal of Physical Chemistry Letters
Joshua M Stratford, Martin Mayo, Phoebe K Allan, Oliver Pecher, Olaf J Borkiewicz, Kamila M Wiaderek, Karena W Chapman, Chris J Pickard, Andrew J Morris, Clare P Grey
The alloying mechanism of high-capacity tin anodes for sodium-ion batteries is investigated using a combined theoretical and experimental approach. Ab initio random structure searching (AIRSS) and high-throughput screening using a species-swap method provide insights into a range of possible sodium-tin structures. These structures are linked to experiments using both average and local structure probes in the form of operando pair distribution function analysis, X-ray diffraction, and (23)Na solid-state nuclear magnetic resonance (ssNMR), along with ex situ (119)Sn ssNMR...
May 16, 2017: Journal of the American Chemical Society
Christoph Kopp, Christian Beyer, Peter Linz, Anke Dahlmann, Matthias Hammon, Jonathan Jantsch, Patrick Neubert, Daniela Rosenhauer, Dominik N Müller, Alexander Cavallaro, Kai-Uwe Eckardt, Georg Schett, Friedrich C Luft, Michael Uder, Jörg H W Distler, Jens Titze
No abstract text is available yet for this article.
April 1, 2017: Rheumatology
Neal K Bangerter, Grayson J Tarbox, Meredith D Taylor, Joshua D Kaggie
Sodium magnetic resonance imaging (MRI), or imaging of the 23Na nucleus, has been under exploration for several decades, and holds promise for potentially revealing additional biochemical information about the health of tissues that cannot currently be obtained from conventional hydrogen (or proton) MRI. This additional information could serve as an important complement to conventional MRI for many applications. However, despite these exciting possibilities, sodium MRI is not yet used routinely in clinical practice, and will likely remain strictly in the domain of exploratory research for the coming decade...
December 2016: Quantitative Imaging in Medicine and Surgery
Christoph Kopp, Christian Beyer, Peter Linz, Anke Dahlmann, Matthias Hammon, Jonathan Jantsch, Patrick Neubert, Daniela Rosenhauer, Dominik N Müller, Alexander Cavallaro, Kai-Uwe Eckardt, Georg Schett, Friedrich C Luft, Michael Uder, Jörg H W Distler, Jens Titze
Objective.: Skin fibrosis is the predominant feature of SSc and arises from excessive extracellular matrix deposition. Glycosaminoglycans are macromolecules of the extracellular matrix, which facilitate Na + accumulation in the skin. We used 23 Na-MRI to quantify Na + in skin. We hypothesized that skin Na + might accumulate in SSc and might be a biomarker for skin fibrosis. Methods.: In this observational case-control study, skin Na + was determined by 23 Na-MRI using a Na + volume coil in 12 patients with diffuse cutaneous SSc and in 21 control subjects...
April 1, 2017: Rheumatology
Zoë E M Reeve, Christopher J Franko, Kristopher J Harris, Hossein Yadegari, Xueliang Sun, Gillian R Goward
(23)Na MAS NMR spectra of sodium-oxygen (Na-O2) cathodes reveals a combination of degradation species: newly observed sodium fluoride (NaF) and the expected sodium carbonate (Na2CO3), as well as the desired reaction product sodium peroxide (Na2O2). The initial reaction product, sodium superoxide (NaO2), is not present in a measurable quantity in the (23)Na NMR spectra of the cycled electrodes. The reactivity of solid NaO2 is probed further, and NaF is found to be formed through a reaction between the electrochemically generated NaO2 and the electrode binder, polyvinylidene fluoride (PVDF)...
January 18, 2017: Journal of the American Chemical Society
James C Pramudita, Aditya Rawal, Mohammad Choucair, Daniele Pontiroli, Giacomo Magnani, Mattia Gaboardi, Mauro Riccò, Neeraj Sharma
Two chemically synthesized defective graphene materials with distinctly contrasting extended structures and surface chemistry are used to prepare sodium-ion battery electrodes. The difference in electrode performance between the chemically prepared graphene materials is qualified based on correlations with intrinsic structural and chemical dissimilarities. The overall effects of the materials' physical and chemical discrepancies are quantified by measuring the electrode capacities after repeated charge/discharge cycles...
December 28, 2016: ACS Applied Materials & Interfaces
Donato Belmonte, Carlo Gatti, Giulio Ottonello, Pascal Richet, Marino Vetuschi Zuccolini
Thermodynamic and thermophysical properties of Na2SiO3 in the Cmc21 structural state are computed ab initio using the hybrid B3LYP density functional method. The static properties at the athermal limit are first evaluated through a symmetry-preserving relaxation procedure. The thermodynamic properties that depend on vibrational frequencies, viz., heat capacities, thermal expansion, thermal derivative of the bulk modulus, thermal correction to internal energy, enthalpy, and Gibbs free energy, are then computed in the framework of quasi-harmonic approximation...
November 10, 2016: Journal of Physical Chemistry. A
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